Hi all – a basic question about having our commcare app capture GPS
– I am aiming to have our app capture GPS coordinates into a normal form
field. (at this point, I’m not looking into the more advanced method of
collecting it automatically without any interaction from the mobile worker.)
– I noticed that using my test phone, which has no SIM card in it, and
when I have turned off Wifi, then the GPS question in the form simply spins
a progress spinner graphic, and never secures any kind of coordinates after
several minutes of waiting.
– So, my basic question… even though my phone (a $120 samsung galaxy
core prime G360) says “GPS” as one of its features, is it pretty normal
that a phone like this could be totally blind to GPS if it has no mobile
data and no wifi signal? In other words, the “GPS” function of the phone
is not independent of those two data signal functions, and GPS isn’t usable
when the phone lacks both of those connections?
On Monday 23 March 2015 22:29:34 Eric Stephan wrote:
> that a phone like this could be totally blind to GPS if it has no mobile
> data and no wifi signal? In other words, the "GPS" function of the phone
I am no GPS expert, but IIRC GPS allows you to download a set of daily information
about satellite positions that help getting a fix. The GPS system broadcast this
data by itself. It takes about 12 minutes (again, if I remember correctly, please take
what I say with a spoon of salt) to get the full set of data.
Now the AGPS system (Assisted GPS) allows you to download the GPS sats data by
other means, much faster. That’s why you get a faster fix when connected.
My point is : have you tried to wait 12/15 minutes to get a first satellite fix ?
I’m using the same phone as you for my project : Samsung Galaxy Core Prime. I’m
going to test the offline GPS fix here in Yangon, Myanmar, and will keep you updated
of my results.
Mine was much slower than one minute… however, I realize that a key point
was: “Going outside.” I forgot that I am sitting inside my office. So I
put the phone by the window and some time later, with zero wifi and zero
mobile data, it did succeed in getting coordinates. Great!
– By the way, how did you determine the number of satellites seen? is that
fact in the android interface somewhere?
– In fact, of course, I hope that our phones will almost always have a
mobile signal, so this scenario should hopefully be rare. But happy to get
– My model number appears to be 360HU, not just H… mine was purchased in
Thailand, maybe that’s the significance of that slight difference?